Can “potato chips” be used to sniff out wildfires before they get out of control?
Well, maybe not potato chips – but thermoelectric ones that are paper-based just might do the trick. This according to researchers reporting in ACS Applied Materials & Interfaces who claim to have developed self-powered “paper chips” that have the ability to sense early fires and relay a signal to responders.
The importance of creating an early warning system has become a priority in the wake of devastating blazes in Australia and the Amazon. Scientists believe that if they can place sensors on trees that will be able to monitor changes in temperature, smoke and humidity, that will give them a leg up to spot and take action to address a potential wildfire threat.
Such a system, however, hasn’t yet seemed practical because all of the sensing components that require power. Batteries that run them eventually go dead and need to be replaced. Thermoelectric materials, which convert temperature differences into electricity, could simultaneously detect temperature increases from fires and power themselves. However, most of these materials are solid inorganic semiconductors, which are often expensive.
The scientists advocating for paper chips, however, believe they have found an answer. As reported by ACS:
“To make paper-based thermoelectric sensors, the researchers chose two ionic liquids that behaved differently when the temperature increased: One adsorbed to the surface of gold electrodes, while the other desorbed, producing opposite (positive or negative) voltages. They deposited each ionic liquid like an ink between two gold electrodes that were sputtered onto a piece of ordinary paper. When connected in series, the two ionic liquids produced an electric signal when a large temperature difference occurred, as would happen in a fire.
In a pilot test of the new sensor, the researchers attached one to a houseplant. When they placed a flaming cotton ball close to the plant’s roots, the temperature at the bottom of the sensor quickly increased, producing a voltage signal that an attached microcomputer chip wirelessly transmitted to a receiver. Upon picking up the signal, the receiver activated a sound alarm and a red light. The thermoelectric paper chips are cheap ($0.04), and the materials are eco-friendly, the researchers say.”
To read the article in its entirety on the ACS website, click here.